1. Field of the Invention
This invention relates to a liquid crystal display apparatus and a method of producing the same.
2. Description of the Prior Art
Liquid crystal display apparatus (LCD) are known and widely in use because the liquid crystal display apparatus are thin and light and requires a low power consumption. The liquid crystal display apparatus comprises two substrates having transparent electrodes, arranged to confront each other with a space in which a liquid crystal is filled.
FIG. 6 is a cross-sectional view of a prior art liquid crystal display apparatus. The prior art liquid crystal display apparatus comprises two substrates 101a and 101b, having transparent electrodes 102a and 102b provided to inner surfaces thereof respectively, arranged to confront each other with a space, a sealing member 104 for supporting sticking, and sealing the substrates 101a and 101b, a liquid crystal 103 filled in the space surrounded by the sealing member 104, and spacers 105 provided between the substrates 101a and 101b. Each of the spacers 105 has a spherical shape for keeping the gap between the substrates 1a and 1b constant. Generally, there is one value of the diameter of the spacer 105. On the other hand, there are another liquid crystal display apparatus having spacers with two different diameters. However, in such a liquid crystal display apparatus, the spaces having two different diameters are uniformly arranged.
FIG. 7A is a plan view of the prior art liquid crystal display apparatus. FIG. 7B is a partial cross-sectional view taken on the line A--A of FIG. 7A. At a displaying portion of the liquid crystal display apparatus (denoted by hatched lines in FIG. 7A), there are the electrodes 102a vertically arranged and the electrodes 102b horizontally arranged. On the other hand, a peripheral portion between the displaying portion and the sealing member 104, there is either of electrodes 102a or 102b. Therefore, as shown in FIG. 7B, a gap between the substrates 101a and 101b at the peripheral portion (substrate gap) is forced to be equal to a gap between the electrodes 102a and 102b (ITO gap) after assembling. This is because the electrode 102a has a thickness and the diameter of the spacer existing at the peripheral portion is the same as the spacer existing at the displaying portion. Accordingly, the substrate 1a is deformed around the edge portion of the display portion, so that the ITO gap at the edge portion of the display portion is smaller than that of the middle portion of the display portion. That is, the interval between the electrodes 102a and 102b at the edge portion of the displaying portion is shorter that at the middle portion of the displaying portion. Thus, there is a problem that uniformly displaying over the displaying portion is difficult in this prior art liquid crystal display apparatus.
Moreover, there is also a problem that at the edge portion of the displaying portion, the uniform displaying is difficult because the resistance from a drive circuit to the electrodes at the edge portion is smaller than that at the middle portion of the displaying portion because a distance from a drive circuit to the electrodes at the edge portion is smaller.
FIG. 8A is a cross-sectional view of a prior art liquid crystal display apparatus with a backlighting source where lamps 10 are provided at both side of a display panel 112 of the liquid crystal display apparatus. FIG. 8B is a plan view of another prior art liquid crystal display apparatus with a backlighting source where the lamps 10 are provided under the display panel 112. In these prior art liquid crystal display apparatus, temperatures of the peripheral areas of the displaying portion is higher than that of the middle portion respectively. Therefore, there is also a problem that at the edged portion of the displaying portion uniform displaying is difficult because of the different in temperature.